DMM Working Group S. Jeon Internet-Draft Sungkyunkwan University Intended status: Standards Track September 11, 2017 Expires: March 15, 2018 Stateless mobility functions draft-sijeon-dmm-stateless-mobility-function-01.txt Abstract This draft presents two use cases to start a talk of stateless mobility function architecture in IETF DMM WG. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on March 15, 2018. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Jeon Expires March 15, 2018 [Page 1] Internet-Draft Stateless mobility functions September 2017 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Mobility function architecture . . . . . . . . . . . . . . . 3 2.1. Integrated state with mobility function . . . . . . . . . 3 2.2. Separated state from mobility function . . . . . . . . . 3 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. Informative References . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction A mobility function could be categorized stateful function and stateless function. The stateful function maintains the state information associated with a terminal or network situation while the stateless function does not keep the state information but only focusing on processing received signaling messages or data packets, as a worker. Combing the state with the worker in the mobility function has basically been considered in many network architectures for easier implementation and negligible latency for accessing the state database without external signaling messages. However, it is nowadays challenging as it tackles the flexibility for network scaling and other enhanced operation support. Separating the control-plane and user-plane makes a progress for the flexible network control and provisioning. That is, a routing controller with holistic view can take a decision of forwarding behavior in the network entities. Stateless user-plane architecture is proposed in [I-D.matsushima-stateless-uplane-vepc], suggesting a mobile architecture that the user-plane network is governed by virtualized EPC decorated with mobility control-plane functions only. The state information the vEPC is holding is transferred by BGP routing to the user-plane architecture. Therefore, the user-plane architecture is totally abstracted and becomes state free, supporting high flexibility in network scaling. Mobility architecture is composed of many control-plane functions. Scale-in/scale-out of those functions is of importance for elastic function resource handling and management (e.g., load balancing). User-plane functions does not generically hold the state information much, so it is relatively easier to do scaling but it is challenging to scale with mobility control-plane functions. Separating the state information from the control-plane functions could facilitate flexible function resource provisioning and expect further enhanced scenarios such as VNF mobility and migration procedure easier. Jeon Expires March 15, 2018 [Page 2] Internet-Draft Stateless mobility functions September 2017 The main objective of this draft is to bring a broad discussion in IETF DMM WG, identifying what needs and requirements for the state separation from a mobility function are existing and what use cases could be meaningful, finally bearing a work item. In this draft, we start with two cases; i) mobility control-plane function integrated with the state information and ii) mobility control-plane function separated from the state information. From the two cases, we check the mentioned aspects. 2. Mobility function architecture 2.1. Integrated state with mobility function Fig. 1 shows the state information is integrated in the mobility control-plane function. Suppose that the mobility control-plane function is composed of state and worker where the work is dedicated to the processing of signaling messages or data packets without concerning or maintaining the state. When the function is instantiated, the state is also initialized within the function. On the other hand, the function needs to be shut down due to some maintenance purpose and the same kinds of a new function is supposed to be initiated, the managed mobility state associated with mobile terminals should be moved to the newly initiated mobility control- plane function through a migration procedure in this case. +-------------+ +-------------+ | State info. | | State info. | +-------------+ +-------------+ | Worker for | | Worker for | | MCP function| | MCP function| +-------------+ +-------------+ Fig. 1. The mobility function integrated with the state information 2.2. Separated state from mobility function Fig. 2 shows the state information is separated from the mobility control-plane function, thus the worker for mobility control-plane function remains in the function. The relationship between the state database and worker can be defined by internal interface or external interface. Following the same scenario described in 2.1, for a need of replacing with a new worker or for scaling out/in, maintaining the state is not constrained, so facilitating various flexibility scenarios. Jeon Expires March 15, 2018 [Page 3] Internet-Draft Stateless mobility functions September 2017 +-------------+ | State info. | +-------------+ | ^ ^ | | | | | v | | v +-------------+ +-------------+ | Worker for | | Worker for | | MCP function| | MCP function| +-------------+ +-------------+ Fig. 2. The mobility function separated from the state information 3. IANA Considerations This document currently makes no request of IANA. 4. Security Considerations 5. Informative References [ETSI.NFV-VNFA] "Network Functions Virtualisation (NFV); Virtual Network Functions Architecture, ETSI GS NFV-SWA 001, v1.1.1", December 2014. [I-D.matsushima-stateless-uplane-vepc] Matsushima, S. and R. Wakikawa, "Stateless user-plane architecture for virtualized EPC (vEPC)", draft- matsushima-stateless-uplane-vepc-06 (work in progress), March 2016. Author's Address Seil Jeon Sungkyunkwan University 2066 Seobu-ro, Jangan-gu Suwon, Gyeonggi-do Korea Email: seiljeon@skku.edu Jeon Expires March 15, 2018 [Page 4]